In a photo taken on August 25, 2014, rescue workers attempt to secure a bus submerged by floodwaters in the southeastern town of Changwon. Five people were killed and five others missing as heavy rains pummelled the southern part of South Korea, rescuers

Five people have been killed and five others are missing after heavy rains pummelled the southern part of South Korea, rescuers said Tuesday.

One person was killed when a commuter bus was swept away by a flash flood into a swollen stream near the city of Changwon on Monday, the National Emergency Management Agency said.

Four others aboard the bus were missing, including the driver. TV footage showed the bus being pulled downstream in muddy flood waters, and overturning before getting stuck beneath a bridge.

Rescuers hammered their way through the windows and pulled out the body of a 19-year-old woman, and were searching for the others still missing.

Four other people were killed as torrential rains battered Busan, South Korea's second largest city.

The victims included two people who were trapped and drowned in their car as they drove through a submerged underpass in Busan.

An engineer was missing after he went down to a flooded building basement to check power lines in the city.

A nuclear power plant in nearby Gijang County was forced to halt operations as a cooling facility was inundated, while heavy rain knocked Busan's subway out of service for hours.

TV footage showed brown water cascading down stairways and escalators into the subway, and inundating railway tracks.

The city was hit by up to 20 centimeters millimeters (eight inches) of rain in the space of just three hours on Monday.

Heavy rain warnings for Busan and the surrounding area were lifted late Monday.